Can a Voltage Spike Fry an Engine?

These are older z-4000’s and it is my belief that they CAN be tightened (as per our friend that owns the body shop).

As for the 25v with a load, THAT is an excellent question.  I hope somebody here can answer it.

I thought that all Z4000s have an adjustment screw on the bottom for each handle that can adjust the tension of the handles.

My z4000's max out a 22 volts. If I quickly raise the handles to max voltage they don't go beyond that level. That's not much of spike compared to what can happen (and how quickly) during a derailment.

TMCC/Legacy is rated at 19VAC maximum.  Putting more voltage on the tracks could certainly have a detrimental effect on your locomotives!

GRJ -

Doing more research on this topic I came across a thread where you mentioned DigiKey part #1.5KE36CA.  These can be installed in the locomotive or at the power source.  Is this item installed in parallel across the post of the Z-4000?

Yes, the TVS is connected across the power source, just like you're trying to short it out.

As far as limiting the track voltage applied by the operator I think I can probably do that via a slight external modification to each handle.

THANKS JOHN, I KNEW YOU WOULD HAVE A SOLUTION. 

Keep in mind that a TVS is a perishable item.  One spike and it may be no longer any good.  And you will have no readily apparent way to tell if there ever was a spike or if the TVS is fried.  A TVS can be difficult to test  because it can fail in more than one way.  I mount them in pairs between my transformer and TIU on each channel that is powered.  About once a year I change them out (they're cheap).  Even then I may be kidding myself that they are always working.  (The TIU has TVS built in, though they used different ones over the years. Some higher, some lower).

While what you say is true, they're not nearly as fragile as you are implying.  Any single spike that takes out a TVS will normally explode it.  They are basically back to back Zener diodes.  There are countless power supplies that use Zener diodes for years and years without failure, and the Zener is in continual breakdown to perform the regulation function.  In real life, TVS protection devices typically have a very long lifetime.  They are not like MOV devices that degrade after each voltage surge, it's a totally different technology.

Thanks for posting that clarification John. It needs to be up on the OGR  top for info in response to a recurring question.

gunrunnerjohn posted:

While what you say is true, they're not nearly as fragile as you are implying.  Any single spike that takes out a TVS will normally explode it.  They are basically back to back Zener diodes.  There are countless power supplies that use Zener diodes for years and years without failure, and the Zener is in continual breakdown to perform the regulation function.  In real life, TVS protection devices typically have a very long lifetime.  They are not like MOV devices that degrade after each voltage surge, it's a totally different technology.

Most devices don't suffer from derailments on a regular basis either.  And Chinese quality control is spotty.  Fact is one good spike can fry a Zener without any "explosion". 

It can, but it's a pretty remote possibility.

I used a lot of TVS devices in aerospace applications, and I can assure you that an airplane at 30,000 to 40,000 feet or flying through a storm is a very hostile place for electronics!

IMO, it's not necessary to double-up on the TVS or replace them nearly as often as you indicate.  Let's agree to disagree on this point.

gunrunnerjohn posted:

It can, but it's a pretty remote possibility.

I used a lot of TVS devices in aerospace applications, and I can assure you that an airplane at 30,000 to 40,000 feet or flying through a storm is a very hostile place for electronics!

IMO, it's not necessary to double-up on the TVS or replace them nearly as often as you indicate.  Let's agree to disagree on this point.

Is a TVS an improvement; yes.  Is it absolute protection; no.  I just don't want people to think they have installed a failsafe security blanket when there is no fool proof way of protecting circuits.  Everything has parameters.  Even though the TIU already has TVS I like redundancy. So yes, we will just have to agree to disagree.   

I shorted  2 internal TIU tvs's do to a dumb.ss connection error. I thought the TIU was done in. The shorted tvs looked "normal" not burnt but immediately would blow 7.5 amp fast blow fuses. New tvs's installed and all good.Got lucky.

Waddy posted:

gunrunnerjohn posted:

It can, but it's a pretty remote possibility.

I used a lot of TVS devices in aerospace applications, and I can assure you that an airplane at 30,000 to 40,000 feet or flying through a storm is a very hostile place for electronics!

IMO, it's not necessary to double-up on the TVS or replace them nearly as often as you indicate.  Let's agree to disagree on this point.

Is a TVS an improvement; yes.  Is it absolute protection; no.  I just don't want people to think they have installed a failsafe security blanket when there is no fool proof way of protecting circuits.  Everything has parameters.  Even though the TIU already has TVS I like redundancy. So yes, we will just have to agree to disagree.   

HUH?  Where did I say it was absolute protection?  Don't put words into my mouth that I didn't speak!

gunrunnerjohn posted:

Waddy posted:

gunrunnerjohn posted:

It can, but it's a pretty remote possibility.

I used a lot of TVS devices in aerospace applications, and I can assure you that an airplane at 30,000 to 40,000 feet or flying through a storm is a very hostile place for electronics!

IMO, it's not necessary to double-up on the TVS or replace them nearly as often as you indicate.  Let's agree to disagree on this point.

Is a TVS an improvement; yes.  Is it absolute protection; no.  I just don't want people to think they have installed a failsafe security blanket when there is no fool proof way of protecting circuits.  Everything has parameters.  Even though the TIU already has TVS I like redundancy. So yes, we will just have to agree to disagree.   

HUH?  Where did I say it was absolute protection?  Don't put words into my mouth that I didn't speak!

Where did I say you said that?  I said that.  TVS is not a failsafe.